1. Field of the Invention
The present invention relates to mutant multi-copper oxidases. More specifically, the invention relates to oxidases which have been modified so as to exhibit altered pH activity profiles relative to the wild-type oxidase.
2. Description of the Related Art
There are currently a number of well-known blue copper oxidases which have various commercial/industrial applications. Two major classes of these enzymes are recognized: (1) the single copper proteins, which are single copper-containing, blue electron-transfer proteins such as plastocyanin, azurin, stellacyanin, amicyanin, auracyanin, cucumber basic blue, mavicyanin, rusticyanin, and urnecyanin; and (2) the multi-copper oxidases, which are multiple copper-containing, blue oxidoreductases such as laccase, bilirubin oxidase, phenoxazinone synthase, ascorbate oxidase, ceruloplasmin, and nitrite reductase. The blue color of these proteins arises from the so-called Type 1 (T1) copper site.
It is an object of the present invention to provide mutants of blue multi-copper oxidases which have improved properties.